A sequence of random variables {Xi} such that the expected value of the (n + 1)th random variable, once the first n outcomes are known, is just the current value Xn. The simple random walk, which moves left or right one step with probability 0.5, is an example of a martingale.
The sequence of random variables X1, X2,…(with finite expected values) is a martingale if the conditional expected value of Xn+1, given the values of X1, X2,…, Xn, is given by
An example is provided by letting Xn be the amount of a gambler's winnings after the nth of a sequence of fair games.
A stochastic process in which the expectation of the future value of a variable, conditional on currently available information, including the current value, is equal to the current value of the variable.
- Duke, Charles Jr (1935– )
- Dulbecco, Renato
- dull emitter
- Dulles, John Foster (1888–1959)
- Dulong and Petit’s law
- Dulong, Pierre-Louis
- Dulong–Petit law
- Duma
- Dumas, Alexandre (1802–70)
- Dumas, Alexandre (1824–95)
- Dumas, Jean Baptiste André
- Dumas, Jean Baptiste André (1800–84)
- Dumas’ method
- Dumbarton Oaks Conference (1944)
- Dumbbell Nebula
- dumb terminal
- Dummett, Michael Anthony Eardley (1925–2011)
- Dummett’s axiom
- dummy activity(in critical path analysis)
- dummy antenna
- dummy instruction
- dummy variable
- dump
- dump check
- dumping